These AMAZING Crystal Bone collars are simply STUNNING !! They are of extremely High Quality, with a very expensive look, but at a REASONABLE price. Each Leash features LEATHER BACKING and Faux Lear Embossed front. The hardware is Polished and Nickle Free. Our Czech Crystals are set using Very Best and Strongest glue setting, with AB Epoxy Glue. AB Epoxy Glue forms a weld like bond and is so strong, that it can actually be drilled. xxsmall is 3/8", small, medium & large are 3/4" COLLAR SIZE CHART Width Length XX-Small 3/8 Inch 6-8 Inches Small 1/2 Inch 9-12 Inches Medium 3/4 Inch 12-16 Inches Large 3/4 Inch 16-18 Inches